1. Field of the Invention
The invention relates to a carrierless electrophoresis method for separating sample substances into their analytes and an electrophoresis device for carrying out this method.
2. Description of Related Art
Known carrierless FFE electrophoresis methods commonly operate with electrophoresis devices whose separation chamber is equipped with only two separate electrode spaces and only one separation space between these electrode spaces.
If, however, the FFE is to be used in the area of proteomics research, it must be possible to separate a large number of different sample substances within a short period, with a maximum separation output and with as high a rate of throughput of sample substances as possible.
However, as in the case of most separation processes, a simultaneous optimization of the electrophoresis device with regard to its separation performance and the sample throughput is difficult. In the case of FFE, simultaneous optimization is only possible within very narrow limits, as an increase in the quantity of the sample substance results in a reduction in the separation performance.
The optimization of the separation performance, moreover, requires a separation space with as narrow and precise a separation chamber gap as possible and specific separation boundary conditions, such as, e.g. a relatively low linear flow rate; as long a separation period as possible; and as many fractionation sites as possible over the entire width of the separation space and/or the area of the separation space in which the sample substance of interest is to be fractionated. However, since the linear flow rate cannot be reduced at will, an extension of the separation time requires a corresponding increase in the length of the electrodes. This in turn means that the outside dimensions of the separation chamber need to be increased simultaneously, making it difficult to manufacture the separation chamber gap with the desired accuracy.
Published German Patent Application DE 2 215 761 A1 discloses an electrophoresis device that operates according to an electrofiltration process. The electrophoresis device is equipped with a separation chamber, electrodes arranged on both sides of the separation chamber, fractionating sites and sample input sites, and several membranes in the separation chamber which divide the separation chamber into a large number of separation spaces connected to each other. The membranes serve as filters and are permeable to the species to be separated off in each case. Additionally, published European Patent Application EP 0 203 713 A2 discloses an electrophoresis device having a separate pair of electrodes for each of the separation spaces bounded by the membranes.